4-hydroxyalkylamino-1, 8-naphthalic acid imide dye salts of oil-solubilizing quaternary ammonium halides



United States Patent once filllflb Patented Sept. 1, 1964 3,147,264 4 ROXYALKYLAMINO 1,8 NAPHTHALHC ACID HMIDE DYE SALTS F OIL-SQLUBILlZlNG QUATERNARY ANMQNIUM HALEDES Arthur F. Klein, Holland, Pa, assignor to American Cg lilalmld Company, New York, N.Y., a corporation 0 arne No Drawing. Filed Mar. 10, 1961, Ser. No. 94,678 8 Claims. (Cl. 26tl-28l) The present invention relates to a novel process for coloring non-polar solvents; making use of available, oilinsoluble 4-hydroxyalkylamino-l,S-naphthalic acid imide dyes which previously could not be used for this purpose. It also contemplates the color-characterizing of liquid fuels. Still more specifically, the invention presents novel, fluorescent, oil-soluble, colored quaternary ammonium reaction products of oil-insoluble, substituted 4-hydroxyalkylarnino-1,8-naphthalic acid imide dyes. It also presents these reaction products in concentrated non-polar solvent solutions which can be easily metered into large quantities of any non-polar solvent. Resultant colored solvents exhibit no functional impairment and are characterized by uniform fluorescent shades, easily detectable both in daylight and black light.

In general, the present invention may be used to color non-polar solvents. As contemplated in the present invention, the term non-polar solvents includes various organic liquid fuels and solvents. They may be classified generally into two broad groups; Group (I) being those of natural origin, and Group (II) synthetic compositions of matter.

Group (I) includes those derived naturally-occurring hydrocarbons such as petroleum ether, having a boiling point of about 60 C.; light naphtha, having a boiling point of about 60 10'0 C.; gasoline, having a boiling point of about 40205 C.; kerosene, having a boiling point of about 175 325 C.; lubricating oils and the like. Depending upon the geographical location from which the crude oil base is obtained from which naturally-occurring hydrocarbons are derived, these bases may be divided into three general types: Type (1), which herein designates the parafiinic type; Type (2), the aromatic type; and Type (3) the mixed type.

The synthetics of Group (II) include such generally synthesized non-polar compounds as carbon tetrachloride, benzene, tetramethyl methane and the like.

For purposes of simplication, novel colored preparations of this invention will be referred to as colorants for jet fuels. However, it is to be understood that the term jet fue as used herein also includes such other fuels and solvents as those noted above, as illustrative.

By way of further illustration, the aircraft industry over the years has developed many types of motor. Some advantageously may use low-octane gasoline. Others require high-octane gasoline for maximum performance. More recently so-called jet motors, which utilize such jet fuels as kerosene and the like, have become important. With the ever increasing use of jet planes, they are found based on locations all over the world. Consequently, there is a need for jet fuels, as well as various grades of gasoline in Widely divergent locations. Furthermore, auxiliary landing fields, with reserve fuel supplies, are required. In such locations, fuels often are delivered and stored in drums. Frequently, too, refueling may be necessary at night. Should this occur, precautions are necessary to insure that each particular plane is serviced with the required type of fuel. Unless these fuels are characteristically marked so that they may be readily identified by night as well as by day, there is a real danger that the wrong fuel might be used.

For these reasons, colorants for such fuels must meet at least 3 requisites, among others.

(1) The colorant should be soluble in all three types of non-polar solvent fuel.

(2) The colorant should be highly and completely oilsoluble, producing no deposits or sludge when used in formulating colored concentrate solutions suitable for metering into the fuels.

(3) The so-colored fuel should be distinguishable in black light as well as daylight.

The term black light as used in this invention refers to ultraviolet light which is invisible to the unaided human eye.

Since the primary purpose is to obtain a characteristic coloring of non-polar solvents including those from bases of Types (1), (2) and (3), it should be noted that to be considered successful, a procedure according to the present invention must meet three additional criteria. It should impart a characteristic, fluorescent, bright color to the jet fuel which will serve to distinguish it in all places at all times. Moreover, the color should be stable, particularly to sunlight. Finally, such a product should be easily and simply prepared.

Gasolines and kerosenes may be and generally are mixtures of many hydrocarbons, including those that are derived from more than one of the three types of base noted above as Type (1), Type (2), and Type (3). Consequently, a jet-fueled plane, of necessity may use fuel from any or all three types. Accordingly a colorant used to characterize jet-fuel, for example, must be highly soluble in each of all three types.

Most presently-used, oil-soluble dyes in general are simple aromatic compounds as compared with many dyes, having relatively few amino, hydroxy, or azo groups and they generally are soluble in hydrocarbons from bases of Types (2) and (3). However, many, if not most, such oil-soluble dyes are noted for their poor solubility in paraffinic hydrocarbons from Type (1). Accordingly, they are unacceptable for the preparation of a universally useful concentrate, characteristically colored, and suitable for metering into hydrocarbon solvents, including hexane, heptane, octane, decane, jet fuels, and the like, derived from Type (1). Presently-used oil-soluble dyes also suffer the further drawback of not being characterized by brilliant fluorescence.

Despite the wide use of these natural non-polar solvents, in the past there has been available no satisfactory, simple process by which they can be satisfactorily color characterized. This problem has proved particularly troublesome with respect to the natural hydrocarbons derived from Type (1) which, in general, are the most difficult to color. Surprisingly, in view of the commercial importance of colorants for characterizing jet fuels and the contemplated dyes for the purpose, in the past it has not been possible to accomplish satisfactory coloring using known dyes. It is a principal advantage of this invention that it fills this need.

Even more surprising is the fact that despite the long felt Want of such a process and colorants therefor, it has been met in the present invention not only to asurprisingly successful degree but by the relatively simple expedient of converting suitable known dyes into their quaternary salts of a particular class of quaternaring halides. It thus provides a simple suitable coloring process for non-polar solvents, particularly for jet fuels, derived from all of Type (1), (2) and (3) bases. It makes possible the preparation of a concentrated solution in hydrocarbon solvents which may be easily metered into jet fuels, imparting thereto bright, fluorescent, characteristic colors. The unexpectedly brilliant fluorescence of the colored fuel is particularly surprising. Last but not least, no observable sedimentation is encountered.

TYPES OF DY ES UTTLIZED As noted above, one of the purposes of this invention is to provide a process by which Type (1) jet fuels can be quickly and characteristically colored, making use of known available dyes which previously could not be so employed. To this end, it is contemplated that this invention may utilize available dyes from the known class of substituted 4-hydroxyalkylamino-1,8-naphthalic acid imide dyes. These dyes generally correspond to the following formula NHR (I) in which R is an alkylol group of less than four carbon atoms and R is a saturated hydrocarbon of less than seven carbons. Specific examples of such dyes will be used below, for purposes of illustration. To simplify reference thereto they will be designated Dyes (A), (8), (C) and (D) respectively, as follows:

TYPES OF QUATERNARY COMPOUNDS UTILTZED As indicated above, dyes utilized in this invention are substituted 4-hydroxyalkylamino 1,8 naphthalic acid imides. They are not soluble in hexane. Unexpectedly, it has been found that they may be made highly and completely oil-soluble by forming a reaction product with certain quaternary ammonium salts. Quaternary salts to be useful in this invention should have at least three special properties:

(1) They should be water-insoluble,

(2) They should be free of hydrogen attached to nitrogen, and

(3) They should be tetra-alkyl quaternary ammonium halides having one or two short-chain alkyl groups and two or three long-chain alky groups.

Suitable halides include chlorides and bromides. When referred to below by the class designation halides it is understood the term is intended to be limited thereto. Suitable short-chain alkyls are methyl, ethyl, propyl, butyl or amyl. Suitable long-chain alkyl groups should contain an average of at least nine but not more than twenty carbon atoms and not only may be saturated (alkyl) or unsaturated (alkenyl) groups, but the same halide may contain both. Advantageously, for example, they may contain such mixtures of alkyl and alkenyl groups as are present in such commercially-available oils such as coconut, soya, tallow and the like. Because such commercially-availabe compositions are not pure products, they will be discussed more fully below, under their ordinary commercial designations coco, soya and stearyl, respectively.

It is uncertain just what product is formed by the reaction of the dyes of this invention and such illustrative tetra-alkyl ammonium halides as those noted above. A

chemical reaction may occur, but the invention is not limited to such a theory. Again, for simplicity in designation, colored products obtained in this reaction will be referred to below as the quaternary salt of the dye or as the dye salt.

The amount of halide to be employed is critical. sufficient halide must be present to completely react with the dye and provide an excess of at least about 0.25 mols per mol. Thus, one molecular weight (average) of the halide per mol of the dye can be reacted but it requires a longer reaction time. Unfortunately and surprising, the resultant dye salt does not impart the desired brilliant shade of fluorescence to hexane and other hydrocarbons of Type (1). To obtain the desired fluorescence a larger quantity of halide must be used. An excess up to a molar ratio of halide to dye of about ten to one produces excellent results. Such a large excess adds unnecessarily to the overall expense and ratios above about 5:1 are not usually warranted. Ratios of from about 1.25:1 to about 5:1 produce satisfactory results and constitute the preferred range.

REACTION TEMPERATURES Although the temperature at which the reaction between the halide and the dye is conducted is important, it is less critical than the molar ratio. Temperatures in the range of from about to about 250 F., may be employed. The higher temperatures are used only for those halides having higher melting points. Use of a temperature in the range of from about to about 225 F. is generally satisfactory and constitutes a good general practice.

REACTION TIME While the reaction time depends to some extent on temperature, a time in the range of from about 10 to about 20 minutes have been found generally sutficient to produce reaction products having satisfactory solubility in hexane as the typical test solvent. However, the reaction should be continued until at least ten grams of the reaction product dissolves readily in 90 grams of hexane without any residual detectable sediment or sludge.

In general terms, preparation of the dye salts according to this invention may be simply described.

(1) In a suitable container, the halide is heated to about E; the halide should be well softened or melted. If not the temperature is increased until this occurs.

(2) The dry dye then is added slowly, with stirring, to the heated halide.

(3) Heating and stirring are continued until the reaction between the quaternary halide and the dye is sufiiciently compieted, i.e., until as noted above at least ten grams of the dye salt dissolves in 90 grams of hexane to a clear, bright color with no observable sedimentation.

Thereafter, concentrated solutions of the dye salt are prepared using any, or all, of the hydrocarbons including those from Types (1) (2) and/or (3). Resultant concentrated solutions should contain from about 0.1 to about 10% of the reaction product. These concentrated solutions may be sent anywhere for coloring native nonpolar solvents including jet fuels. Alternatively, the dye salt may be shipped per se with suitable instructions and used wherever so-desired to produce the colored concentrates for metering into the large masses of non-polar solvents to be colored.

As noted above, colored concentrated solutions may also be used for other purposes as by being thickened with an oil-soluble cellulose derivative, or its equivalent. It also may be converted into emulsions for use in coloring various fibrous or other materials, including sheets, films, resins, yarns, fabrics and the like.

It is a still further advantage that jet fuels colored with about 0.0020.0l% weight percent of the above colorants will acquire bright, characteristic fluoroscent shades using any one, or a combination, of hydrocarbons from Types (1) (2) and (3).

The invention will be further illustrated in conjunction with the following discussion and the accompanying examples of the use of the tetra-alkyl ammonium halides. These examples are illustrative only. Therein, unless otherwise noted, all parts and percentages are by weight and temperatures are in Fahrenheit degrees. Reactions are described using molar quantities of the halide and Dyes (A) (B) (C) and (D) noted above. The number 267 was used as the molecular weight of trimethyl monococo ammonium chloride; the number 450 was used as the molecular weight of di-methyl-di-coco ammonium chloride; the number 566 was used as the molecular weight of di-methyl di-soya ammonium chloride; and the number 571 was used as the molecular weight of dimethyl di-stearyl ammonium chloride. Molecular weights of the di-ethyl, di-propyl, di-butyl and diamyl compounds may be easily calculated from the above numbers if necessary or so desired.

In the following Examples 1-7, the halide is reacted with the dye according to the following procedure.

Solubility tests of the reaction products is observed by stirring one gram of the colored dye salt into 100 ml. of the test solvent.

To demonstrate the unsatisfactory nature of dye salts 3 from halides containing three short-chain alkyl groups and only one long-chain, in the following example a commercially-available trimethyl-mono-coco ammonium chloride was used. The coco portion of the quaternary compound is a mixed commercial alky comprising generally about 8% octyl, 9% decyl, 47% dodecyl, 18% tetradecyl, 8% hexadecyl and octadecyl groups. The equivalent or molecular weight of the chloride is calculated to be about 267.

Example 1 Four reaction products of each of the four dyes (A) (B) (C) and (D) are prepared using the following ratios: (a) one equivalent of the chloride and one equivalent of each dye; (b) 1.25 equivalents of the chloride and one equivalent of the dye; (c) four equivalents of the chloride and one equivalent of imide dye; and, (d) eight equivalents of the chloride and one equivalent of the dye. The sixteen resultant products are then tested for the solubility of one gram of dye salt in 100 grams each of water and of kerosene as a typical jet fuel. Results are summarized in the following Table I.

It may be observed from Table I that, none of the reaction products are soluble in kerosene; when the ratio of the tri-methyl mono-coco ammonium chloride is in a range of about 4-8, the colored reaction products are water-soluble; the 421 product showing slight cloudiness, indicating incomplete solubility, but however, the 8/1 product give a clear solution indicating complete solubility in water.

To illustrate the effect of halides having both two short and two long-chain alkylo groups the following example was carried out using a commercially-available di-methyl-di-coco ammonium chloride. The equivalent or molecular weight of the chloride is calculated to be about 450.

Example 2 TAB LE II E quivalents of Dye E quivalents of Halide Soluble Dye Kerosene S1. Cloudy. Yes (clear). Do.

As compared with Table I it will be seen that excellent solubility in kerosene is obtained in the range halide: dye ratios of about 1.25:1 to about 8:1; none of the products is Water soluble. The reaction products formed using the 1:1 ratio show slight cloudiness in kerosene, indicating that this reaction product is not as completely soluble as the others.

Example 3 Twenty parts of dye salt, prepared above in Example 2 from Dye (A) and chloride in 1:4 ratio are dissolved in parts of kerosene, imparting to the nonpolar solvent a bright, greenish-yellow, fluorescent color. The dye salt is also equally soluble in equivalent amounts in hexane, gasoline, and jet fuel.

The 20% solution in kerosene is metered into one gallon of kerosene to give about 0.0010.01% concentration. A characteristic greenish-yellow, fluorescent color is imparted. This characteristic color is visible both in daylight and in black light.

Example 4 The procedure of Example 2 is repeated, using as the halide a commercially-available di-methyl di-soya ammonium chloride instead of the di-methyl di-coco ammonium chloride. The soya component comprises about 24% hexadecyl, 4% octadecyl, 30% octadecenyl, and 42% octadecadienyl components. The molecular or equivalent Weight of this compound is calculated to be about 566. Colored dye salts of the twelve reaction products obtained in the ratios from a range of 1.25:1; 4:1; and 8:1 are readily soluble in hexane, gasoline, kerosene, and jet fuel.

Example Twenty parts of the quaternary salt of the dye, prepared in Example 4 from Dye (A) using the 4:1 ratio are dissolved in 80 parts of kerosene, imparting a bright, greenish-yellow, fluorescent color to this non-polar solvent. This reaction product also is equally soluble in hexane, jet fuel and gasoline. Portions of the above concentrated solution are metered into lubricating oils having S.A.E. ratings of 10, 30 and 60. In each instance, a characteristic greenish-yellow, fluorescent color is imparted to the oil.

Example 6 Portions of the concentrated solution produced in Example 5 are metered into kerosene to give a concentration of the colored component of about 0.002%. A greenish-yellow, fluorescent color results which is visible in daylight and in black light. When the concentration of the colored component is increased to about 0.0075 the greenish-yellow, fluorescent color is intensified.

Example 7 The procedure of Example 2 is repeated substituting a commercially-available quaternary saltdi-methyl distearyl ammonium chloride. The stearyl component comprises about 75% octadecyl, 24% hexadecyl, and 1% octadecenyl components. The molecular weight of this compound is calculated to be about 57-1. Colored reaction products of the various dyes prepared in the ratio range of from about 1.25:1 to about 8:1 are soluble in gasoline and kerosene.

Example 8 Ten parts of the reaction product, prepared in Example 7 from Dye (A) at the 4:1 ratio are dissolved in 90 parts of gasoline. Suflicient of this concentrated solution is then metered into one gallon of jet fuel to give a con centration of the colored component of about 0.001% on the weight of the jet fuel. A characteristic, greenishyellow, fluorescent color is imparted to the jet fuel. It is readily distinguished in daylight and in black light. When the concentration of the colored component is increased to about 0.01%, this characteristic color is intensified.

Example 9 Using one equivalent of Dye (A) and four equivalents of di-methyl di-coco ammonium chloride, the procedure of Example 2 is repeated at a temperature of about 175 F. The resulting dye salt is soluble in gasoline and kerosene. In coloring eflectiveness the product is the equivalent of the corresponding product obtained in Example 2.

Example 10 Example 9 is repeated, using a reaction temperature of about 225 F. The reaction between the dye and chloride is very rapid at this temperature. The product is substantially the same, being soluble in gasoline, and imparting a characteristic, greenish-yellow, fluorescent color to the non-polar solvent.

I claim:

1. A water-insoluble colored salt, soluble in non-polar solvents, comprising a dye salt produced by melting together at about 100-250 F. until a clear hexanesoluble product is obtained (a) from about 1.25 to about 10 moles and suflicient to completely react with the dye of a halide of the formula wherein (Hal) is selected from the group consisting of chlorine and bromine; each R is a long-chain hydrocarbon selected from the group consisting of alkyl and alkenyl containing from about nine to about twenty carbons; R is an alkyl of less than six carbon atoms; and R is selected from R and R and (b) one mole of an 5 N-substituted 4-hydroxyalkylamino-1,8-naphthalic acid imide of the formula t" 10 I k 3 wherein R is an alkylol having less than four carbons and R is a saturated hydrocarbon of less than seven carbons.

2. A method for the preparation of the dye salt of claim 1 comprising the steps of heating said tetra-alkyl quaternary ammonium halide until liquifaction occurs, then adding the dry imide dye slowly, with stirring, at a temperature in the range of from 100 F. to about 250 F., and continuing heating and stirring until 10 parts by weight of the product is soluble in 90 parts of hexane.

3. A water-soluble colored salt, soluble in non-polar solvents, comprising a dye salt produced by melting together at about 100-250 F. until a clear hexanesoluble product is obtained a quantity sufiicient to completely react with the dye and within the range of from about 1.25 to about 10 mols of di-coco-dialkylammonium chloride in which each of the two alkyls contains less than six carbon atoms and one mol of an N-substituted 4-hydroxyalkylamino-1,8-naphthalic acid imide of the formula -O T i wherein R is an alkylol having less than four carbons and R is a saturated hydrocarbon of less than seven carbons.

4. A water-soluble colored salt, soluble in non-polar solvents, comprising a dye salt produced by melting together at about 100-250 F. until a clear hexanesoluble product is obtained a quantity suflicient to completely react with the dye and within the range of from about 1.25 to about 10 mols of di-soya-dialkylammonium chloride in which each of the two alkyls contains less than six carbon atoms and one mol of an N-substituted 4-hydroxyalkylamino-1,8-naphthalic acid imide of the formula wherein R is an alkylol having less than four carbons and R is a saturated hydrocarbon of less than seven carbons.

5. A water-soluble colored salt, soluble in non-polar solvents, comprising a dye salt produced by melting together at about -250 F. until a clear hexanesoluble product is obtained a quantity sufficient to completely react with the dye and within the range of from about 1.25 to about mols of di-stearyl-dialkylammonium chloride in which each of the two alkyls contains less than six carbon atoms and one mol of an N-substituted 4-hydroxyalkylamino-1,8-naphthalic acid irnide of the formula wherein R is an alkylol having less than four carbons and R is a saturated hydrocarbon of less than seven carbons.

7. A water-soluble colored salt, soluble in non-polar solvents, comprising a dye salt produced by melting together at about 100250 F. until a clear hexanesoluble product is obtained a quantity suflicient to completely react with the dye and within the range of from about 1.25 to about 10 mols of tri-soya-monoalkylamrnonium chloride in which the alkyl contains less than six 1 carbon atoms and one mol of an N-substituted 4-hydroxyalkylamino-1,8-naphthalic acid imide of the formula wherein R is an alkylol having less than four carbons and R is a saturated hydrocarbon of less than seven carbons. 8. A water-soluble colored salt, soluble in non-polar solvents, comprising a dye salt produced by melting together at about l00250 F. until a clear hexanesoluble product is obtained a quantity sufiicient to completely react with the dye and within the range of from about 1.25 to about 10 mols or" tri-stearyl"-monoalkylammonium chloride in which the alkyl contains less than six carbon atoms and one mol of an N-suostituted 4-hydroxyalkylamino-1,8-uaphthalic acid irnide of the formula wherein R is an alkylol having less than four carbons and R is a saturated hydrocarbon of less than seven carbons.

References Cited in the file of this patent UNITED STATES PATENTS 1,969,249 Allernan Oct. 9, 1933 2,224,904 Elley et al. Dec. 17, 1940 2,385,106 Scalera et a1 Sept. 18, 1945 2,749,346 Hoffmann et a1. June 5, 1956 2,798,070 Cain July 2, 1957 2,812,350 Niederhauser Nov. 5, 1957 2,828,316 Pacini et al Mar. 25, 1958 

1. A WATER-INSOLUBLE COLORED SALT, SOLUBLE IN NON-POLAR SOLVENTS, COMPRISING A DYE SALT PRODUCED BY MELTING TOGETHER AT ABOUT 100*-250*F. UNTIL A CLEAR HEXANESOLUBLE PRODUCT IS OBTAINED (A) FROM ABOUT 1.25 TO ABOUT 10 MOLES AND SUFFICIENT TO COMPLETELY REACT WITH THE DYE OF A HALIDE OF THE FORMULA 